Nowadays, use of flashlights in the field of tactics is increasingly emphasized. During confrontation of two armies in the darkness, directly irradiating eyes of enemies with light beams to disable the enemies to identify own accurate positions may effectively increase a probability of winning in this confrontation. When breaking into rooms for assaulting, soldiers and police can use constant beam or strobe irradiation to get the other party in control. In such an emergency, a tactical flashlight which may be simply operated with one hand and may enter a momentary activation (constant beam) or strobe mode is required. For realizing such a function, a reliable mechanical switch capable of enable the flashlight to enter the strobe mode or the momentary activation mode with a key is required.